GCDAProfiling.c revision ec63f456de18b9ac75d7546f8a53beb6ce048e67
1/*===- GCDAProfiling.c - Support library for GCDA file emission -----------===*\ 2|* 3|* The LLVM Compiler Infrastructure 4|* 5|* This file is distributed under the University of Illinois Open Source 6|* License. See LICENSE.TXT for details. 7|* 8|*===----------------------------------------------------------------------===*| 9|* 10|* This file implements the call back routines for the gcov profiling 11|* instrumentation pass. Link against this library when running code through 12|* the -insert-gcov-profiling LLVM pass. 13|* 14|* We emit files in a corrupt version of GCOV's "gcda" file format. These files 15|* are only close enough that LCOV will happily parse them. Anything that lcov 16|* ignores is missing. 17|* 18|* TODO: gcov is multi-process safe by having each exit open the existing file 19|* and append to it. We'd like to achieve that and be thread-safe too. 20|* 21\*===----------------------------------------------------------------------===*/ 22 23#include <stdio.h> 24#include <stdlib.h> 25#include <string.h> 26#include <sys/stat.h> 27#include <sys/types.h> 28#ifdef _WIN32 29#include <direct.h> 30#endif 31 32#ifndef _MSC_VER 33#include <stdint.h> 34#else 35typedef unsigned int uint32_t; 36typedef unsigned int uint64_t; 37#endif 38 39/* #define DEBUG_GCDAPROFILING */ 40 41/* 42 * --- GCOV file format I/O primitives --- 43 */ 44 45static FILE *output_file = NULL; 46 47static void write_int32(uint32_t i) { 48 fwrite(&i, 4, 1, output_file); 49} 50 51static void write_int64(uint64_t i) { 52 uint32_t lo = i >> 0; 53 uint32_t hi = i >> 32; 54 write_int32(lo); 55 write_int32(hi); 56} 57 58static uint32_t length_of_string(const char *s) { 59 return (strlen(s) / 4) + 1; 60} 61 62static void write_string(const char *s) { 63 uint32_t len = length_of_string(s); 64 write_int32(len); 65 fwrite(s, strlen(s), 1, output_file); 66 fwrite("\0\0\0\0", 4 - (strlen(s) % 4), 1, output_file); 67} 68 69static char *mangle_filename(const char *orig_filename) { 70 char *filename = 0; 71 int prefix_len = 0; 72 int prefix_strip = 0; 73 int level = 0; 74 const char *fname = orig_filename, *ptr = NULL; 75 const char *prefix = getenv("GCOV_PREFIX"); 76 const char *tmp = getenv("GCOV_PREFIX_STRIP"); 77 78 if (!prefix) 79 return strdup(orig_filename); 80 81 if (tmp) { 82 prefix_strip = atoi(tmp); 83 84 /* Negative GCOV_PREFIX_STRIP values are ignored */ 85 if (prefix_strip < 0) 86 prefix_strip = 0; 87 } 88 89 prefix_len = strlen(prefix); 90 filename = malloc(prefix_len + 1 + strlen(orig_filename) + 1); 91 strcpy(filename, prefix); 92 93 if (prefix[prefix_len - 1] != '/') 94 strcat(filename, "/"); 95 96 for (ptr = fname + 1; *ptr != '\0' && level < prefix_strip; ++ptr) { 97 if (*ptr != '/') continue; 98 fname = ptr; 99 ++level; 100 } 101 102 strcat(filename, fname); 103 104 return filename; 105} 106 107static void recursive_mkdir(char *filename) { 108 int i; 109 110 for (i = 1; filename[i] != '\0'; ++i) { 111 if (filename[i] != '/') continue; 112 filename[i] = '\0'; 113#ifdef _WIN32 114 _mkdir(filename); 115#else 116 mkdir(filename, 0755); /* Some of these will fail, ignore it. */ 117#endif 118 filename[i] = '/'; 119 } 120} 121 122/* 123 * --- LLVM line counter API --- 124 */ 125 126/* A file in this case is a translation unit. Each .o file built with line 127 * profiling enabled will emit to a different file. Only one file may be 128 * started at a time. 129 */ 130void llvm_gcda_start_file(const char *orig_filename) { 131 char *filename = mangle_filename(orig_filename); 132 output_file = fopen(filename, "w+b"); 133 134 if (!output_file) { 135 recursive_mkdir(filename); 136 output_file = fopen(filename, "w+b"); 137 if (!output_file) { 138 fprintf(stderr, "profiling:%s: cannot open\n", filename); 139 return; 140 } 141 } 142 143 /* gcda file, version 404*, stamp LLVM. */ 144#ifdef __APPLE__ 145 fwrite("adcg*204MVLL", 12, 1, output_file); 146#else 147 fwrite("adcg*404MVLL", 12, 1, output_file); 148#endif 149 150#ifdef DEBUG_GCDAPROFILING 151 printf("llvmgcda: [%s]\n", orig_filename); 152#endif 153 154 free(filename); 155} 156 157/* Given an array of pointers to counters (counters), increment the n-th one, 158 * where we're also given a pointer to n (predecessor). 159 */ 160void llvm_gcda_increment_indirect_counter(uint32_t *predecessor, 161 uint64_t **counters) { 162 uint64_t *counter; 163 uint32_t pred; 164 165 pred = *predecessor; 166 if (pred == 0xffffffff) 167 return; 168 counter = counters[pred]; 169 170 /* Don't crash if the pred# is out of sync. This can happen due to threads, 171 or because of a TODO in GCOVProfiling.cpp buildEdgeLookupTable(). */ 172 if (counter) 173 ++*counter; 174#ifdef DEBUG_GCDAPROFILING 175 else 176 fprintf(stderr, 177 "llvmgcda: increment_indirect_counter counters=%x, pred=%u\n", 178 state_table_row, *predecessor); 179#endif 180} 181 182void llvm_gcda_emit_function(uint32_t ident, const char *function_name) { 183#ifdef DEBUG_GCDAPROFILING 184 printf("llvmgcda: function id=%x\n", ident); 185#endif 186 if (!output_file) return; 187 188 /* function tag */ 189 fwrite("\0\0\0\1", 4, 1, output_file); 190 write_int32(3 + 1 + length_of_string(function_name)); 191 write_int32(ident); 192 write_int32(0); 193 write_int32(0); 194 write_string(function_name); 195} 196 197void llvm_gcda_emit_arcs(uint32_t num_counters, uint64_t *counters) { 198 uint32_t i; 199 200 /* Counter #1 (arcs) tag */ 201 if (!output_file) return; 202 fwrite("\0\0\xa1\1", 4, 1, output_file); 203 write_int32(num_counters * 2); 204 for (i = 0; i < num_counters; ++i) 205 write_int64(counters[i]); 206 207#ifdef DEBUG_GCDAPROFILING 208 printf("llvmgcda: %u arcs\n", num_counters); 209 for (i = 0; i < num_counters; ++i) 210 printf("llvmgcda: %llu\n", (unsigned long long)counters[i]); 211#endif 212} 213 214void llvm_gcda_end_file() { 215 /* Write out EOF record. */ 216 if (!output_file) return; 217 fwrite("\0\0\0\0\0\0\0\0", 8, 1, output_file); 218 fclose(output_file); 219 output_file = NULL; 220 221#ifdef DEBUG_GCDAPROFILING 222 printf("llvmgcda: -----\n"); 223#endif 224} 225